The present invention relatives generally to structural panel systems used as building components, and more particularly to structural panels useful in constructing translucent or transparent wall structures such as those used in skylight systems. Panels of the invention have a unique composite construction providing improved panel integrity especially wherein components of the panel are constructed of materials having differing coefficients of thermal expansion.
As further background to the invention, translucent and/or transparent wall systems, such as those used in skylights, have long been used in the building industry to provide a esthetic value and illuminate interiors of buildings. Such systems typically have a metal gridwork and, received in the gridwork, a plurality of translucent or transparent panels. Historically, these panels have been constructed having a metal frame such as aluminium, each side of which is covered by a facing material. In turn, the facing material has historically often been constructed of a non-metal material, such as fiberglass or plastic, most notably in industry fiberglass, which has been bonded to the metal frame.
A problem encountered with such panel constructions is that the materials of the frame and the facing often have differing coefficients of thermal expansion. When this is the case, differential expansion of the frame and facing create stress on the bonds between them and) where the facing has a greater coefficient of thermal expansion, can cause the facing to become rounded or "pillowed" when subjected to heat.
U.S. Pat. No. 3,967,423 to Hammond is illustrative of such systems having the facing bonded directly to the panel frame. Particularly, the Hammond patent describes a skylight panel comprised of an extruded aluminium frame of rectangular outline. The panel of Hammond is closed on both sides by translucent facing which is made of a tough, durable plastic bonded at the margins to the outer edges of the frame.
U.S. Pat. No. 3,886,706 to Baker describes building sandwich panels having facing panels removably supported on a load-carrying frame. The removable support facilitates assembly at a building site and repair thereafter.
In light of the background in the area, there is a need and demand for improved panel constructions overcoming difficulties presented by prior constructions. The applicants' invention addresses this need.